In the development of chrome free process of refractory materials used for RH refining furnace,magnesium aluminum spinel non-fired bricks have been tested as the best alternative products for electrofusion and recombination of magnesium chromium bricks.Through static crucible test,the slag resistance experiment is carried out on the MgO-MgAl2O4-Al composite material and the residual bricks used in the RH furnace are compared and analyzed.It is found that the slag layer,the erosion layer and the original brick layer form both in the crucible and the residual brick of the RH furnace during the slag resistance test.The microstructures of the slag layer,the erosion layer and the original brick layer are analyzed by scanning electron microscope.It is found that the microstructure of the crucible in slag resistance test under laboratory conditions is different from that of the residual brick on site.The results show that firstly the slag layer,the erosion layer and the original brick layer form in the residual brick used in RH furnace,and the phases in the slag layer are mainly periclase,magnesium aluminum spinel,iron oxide solid solution and calcium aluminate phase,secondly a dense periclase zone forms in the erosion layer,thirdly Mg-A1-(Si)-O-N non-oxide forms by the reaction of aluminium powder with MgAl2O4 and MgO,which is analyzed on residual bricks used in the RH furnace and improves the slag resistance.The MgO-MgAl2O4-Al composite has a good anti-slag resistance in the hot parts such as RH furnace trough,impregnated pipe and circulation pipe.

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